1. Field of the Invention
This invention relates generally to a die for holding a nutplate and for aligning rivets relative thereto and, more particularly, to an automatic nutplate die for holding and aligning a plurality of rivets with holes in the nutplate and holes in a structure that the nutplate is being secured to so that the rivets can be simultaneously formed by a single operation of a rivet squeezer.
2. Discussion of the Related Art
Nutplates are often used to connect various parts and components together for different applications, such as aircraft bulkheads and the like. A nutplate is a connector assembly that includes a base plate having edges that are formed to loosely hold a connector to the nutplate. Each nutplate is secured to a part by a pair of rivets, where the connector is typically positioned between the rivets. Cooperating nutplates are secured to another part, and the connectors are engaged to connect the parts together. Certain assemblies, such as certain spacecraft assemblies, may employ more than 3000 nutplates.
The base plate of the nutplate and the part that the nutplate is being mounted to include pre-drilled holes. The assembler aligns a hole in the base plate with the appropriate hole in the part, and then pushes a rivet through a back side of the part so that it extends through the base plate of the nutplate. The rivet includes a head that is positioned within a counter sunk bore in the back side of the part. The other rivet is then pushed through the part and the nutplate in the same manner. A cap block is held against the two rivets to hold them in place prior to forming the rivets. The assembler to aligns a punch of a rivet squeezer with the unformed end of one of the rivets opposite to the counter sunk bore, and then forms the end of the rivet with the squeezer to secure the nutplate to the part. The operator then aligns the punch of the squeezer with the other rivet to form it in the same manner. Thus, the nutplate is securely attached to the part. Different types of nutplates are known in the art and different types of rivet squeezers are used to secure the nutplates to the part.
Installing nutplates in this manner is extremely labor intensive and time-consuming. Additionally, because the operator is required to align the punch of the squeezer with the rivets, a certain amount of skill is required to accurately perform the riveting process. If the punch and rivet are not properly aligned, the poorly punched rivets must be drilled out, possibly damaging the nutplate in the process, and further adding to the cost of the process.
What is needed is a device for aligning the punch with the rivet when assembling a nutplate to a part to provide a more cost-effective way to speed up the riveting process. It is therefore an object of the present invention to provide such a device.
In accordance with the teachings of the present invention, an automatic nutplate die is used to align a plurality of rivet punches with a plurality of rivets being used to secure a nutplate to a part by a rivet squeezer. The nutplate die includes a nutplate platen and a punch platen secured to each other by a pair of stripper bolts. The stripper bolts included threaded portions that are threaded into the punch platen, and bolt heads that are positioned within counter-sunk bores in the nutplate platen. A spring is positioned on the shaft portion of each of the bolts. The rivet punches are rigidly secured to the punch platen, and are slidably engaged within opposing bores in the nutplate platen. The nutplate platen includes a cavity that accepts the nutplate so that holes in the nutplate are aligned with the bores and the punches.
The nutplate is positioned within the cavity, and the rivets are positioned through the part and the nutplate while it is in the cavity. Activation of the rivet squeezer causes the nutplate platen to move toward the punch platen against the bias of the springs so that the punches move through the bores and contact the unformed ends of the rivets, thus forming the ends of the rivets to secure the nutplate to the part. In this manner, both of the rivets are formed with one operation of the squeezer. When the squeezer is released, the springs cause the nutplate platen to move away from the punch platen until the heads of the stripper bolts contact the counter-sunk bores.
Additional advantages and features of the present invention will become apparent to those skilled in the art from the following discussion and the accompanying drawings and claims.